Hi all,

I've been dealing with elevated Long Term Fuel Trim values on my 2020 Focus MK4 1.0 EcoBoost 125hp (B7DA, ~77k miles). No check engine light, no fault codes stored.

Current LTFT values per Cell stored in ECU:

Cell	Value
Cell 1	2.34%
Cell 2	7.03%
Cell 3	7.03%
Cell 4	11.72%
Cell 5	7.03%
Cell 6	10.16%

In my opinion those numbers are quite high for an EcoBoost just 6.5 years old. The issue is most noticeable under load — highway driving especially. At idle cell 1 looks almost normal but the others are clearly elevated.

Symptoms:

• Occasional hesitation/misfire feel under load

• Higher than expected fuel consumption

• LTFT values have been progressively worsening since purchase

I've attached a FORScan log showing the elevated LTFT values while driving. No vacuum leaks found visually but haven't done a smoke test yet. MAF and sensors look okay visually.

Has anyone experienced similar on the MK4 1.0 EcoBoost? Any known issues or things to check first? Around row 3534 the LTFT jumps to over 10%.

Log File (XLSX)

Thanks for you help!

Have you replaced the plugs recently?

The plugs have been replaced last year during maintaince at Ford, thats just about 7000 km (4.350 miles) ago, odo meter was back then 119000 km (73.950 miles)

yesterday i checked all the hoses for possible air leaks and found that that the hose from the turbo charge to the intercooler was a bit loose, i could it move it back and for so thats not good.

I noticed also that hose was vibrating heavily, im not sure if this is normal for the ecoboost but i can understand that will losen the connection overtime.

I didnt had the right tools to refit it directly but managed to tighten it a bit, this massivly improved my trim values only driving above 100 km/h its still too bit too lean but

i hope if clean the hose and refit it, it will go down further. Im only curious if its normal that this hose is vibrating so heavily while running idle?


The trim table now:

LFT1_CELL1	-2,34	(%)
LFT1_CELL2	2,34	(%)
LFT1_CELL3	3,12	(%)
LFT1_CELL4	10,16	(%)
LFT1_CELL5	3,91	(%)
LFT1_CELL6	10,16	(%)